22. Extract Even Bits Only from 32-bit Register

#include <stdio.h>
#include <stdint.h>

uint32_t extract_even_bits(uint32_t reg) {
    // Your code here
    uint32_t count = 0;
    uint32_t ret_val = 0;
    while (reg)
    {
        if(reg & 0x00000001)
        {
            count++;
        }
        reg = reg>>2;
    }
    ret_val = (1<<count)-1;
    return ret_val;
}

int main() {
    uint32_t reg;
    scanf("%u", &reg);
    printf("%u", extract_even_bits(reg));
    return 0;
}